It is essential that the conditions within a medical operating room be maintained as germ free as possible. The cleanliness and sterile nature of an operating room environment are dictated by considerations concerning the health of the patient, as well as institutional and personal liability.
A required apparel worn by persons in a medical operating room is a face mask. While the cleanliness of the operating room equipment, as well as the occupants, can be carefully controlled, the cleanliness of the air within the operating room is less controllable. The surgical face masks, therefore, serve as a device for maintaining inhaled or exhaled germs from contaminating the operating room environment.
Great strides have been made in the medical supply field for providing comfortable and effective face masks. Materials are available for allowing the free passage of air through the face mask for breathing, and for preventing the permeation of germs therethrough. Because operating room personnel may be required to wear surgical face masks for extended periods of time, such masks must also be comfortable, and must be structured so as not to interfere with the breathing or the line of sight vision of the wearer. An ever present problem attendant with the use of surgical face masks is the warm, moist air exhaled by the wearer. The exhaled air has a tendency to fog or cloud eyeglasses, or other equipment such as microscopes. This fogging or clouding is a result of the high concentration of moisture vapor contained within the mask which, when diffused through the face mask material, condenses on the cooler eyeglass surfaces in the proximity of the mask.
This problem has not gone unaddressed in the art, and indeed many attempts have been made to provide masks which reduce such fogging and clouding effects. One approach utilized is the attachment of an impervious material on the top inside part of the mask to completely block the movement of all air through the top part of the mask. While this approach reduces the fogging tendency to a certain extent, it also reduces the area of the mask through which air can be breathed. In addition, there is a tendency, due to perspiration on the material, for the mask to cling to the wearer's face. This problem was later overcome by adhering an open-celled synthetic foam material to the impervious material to thereby eliminate the direct contact of the material with the wearer's face.
Other approaches taken by those familiar with the art are disclosed in U.S. Pat. No. 3,888,246. The barrier disclosed in this patent involves the use of a lightweight plastic film attached to the upper edge of the face mask material. Again, the disadvantage of the use of a plastic film is that when perspiring the mask tends to adhere to the wearer, much like the impervious material noted above. Moreover, when the impervious strip is placed on the outside surface of the mask, the exhaled vapor may yet condense on the plastic and cause an undesirable situation.
Disclosed in U.S. Pat. Nos. 3,474,829 and 4,037,593 is an air impervious vapor barrier used in connection with a surgical face mask. The vapor barrier comprises either an open-celled foam covered with an impervious sheet, or a closed cell foam.
Another source of contamination stems from the fibrous material of the face mask itself. Present face masks generally utilize a sewing operation in the fabrication thereof which requires a needle to pierce the fibrous material in order to form seams. This procedure results in the needle carrying the fibers through the material to the outside to potentially contaminate the environment. Also, the perforations made by the needle provide passages for contaminates to pass through. With such masks, the fibers released by the sewing operation may be breathed by the mask wearer, as the wearer is continually inhaling and exhaling through the mask. This is an undesirable condition in that it is of primary importance that all sources of contamination be minimized to any extent possible.
There is therefore a need for a noncontaminating surgical face mask which is both superior in its ability to prevent moisture vapor from escaping through the top portion of the mask, while yet allowing the free movement of air therethrough to facilitate breathing. There is also an associated need for a face mask which is comfortable to wear over an extended period of time, and in addition, which is economical and easily manufacturable.